<template>
    <div class="star" :class="starType">
       <span v-for="itemClass in itemClasses" :class="itemClass" class="star-item"></span>
    </div>
</template>

<script>
    const LENGTH = 5;
    const CLS_ON = 'on';
    const CLS_HALF = 'half';
    const CLS_OFF = 'off';
    export default {
      props: {
        size: {
          type: Number
        },
        score: {
          type: Number
        }
      },
      computed: {
        starType() {
          return 'star-' + this.size;
        },
        itemClasses() {
          let result = [];
          let score = Math.floor(this.score * 2) / 2;
          let hasDecimal = score % 1 !== 0;
          let integer = Math.floor(score);
          for (let i = 0; i < integer; i++) {
            result.push(CLS_ON);
          }
          if (hasDecimal) {
            result.push(CLS_HALF);
          }
          while (result.length < LENGTH) {
            result.push(CLS_OFF);
          }
          return result;
        }
      }
    };
</script>
<style lang="less"  rel="stylesheet/less" type="text/less">
  .star {
    .star-item {
      font-size: 0;
      display: inline-block;
      background-repeat: no-repeat;
    }
    &.star-24 {
      .star-item {
        width: 10px;
        height: 10px;
        margin-right: 3px;
        background-size: 10px 10px;
        &:last-child {
          margin-right: 0;
        }
        &.on {
           background-image: url('star24_on@2x.png');
            @media(-webkit-min-device-pixel-ratio: 3),(min-device-pixel-ratio: 3) {
             background-image: url('star24_on@3x.png');
            }
        }
        &.half {
           background-image: url('star24_half@2x.png');
            @media(-webkit-min-device-pixel-ratio: 3),(min-device-pixel-ratio: 3) {
             background-image: url('star24_half@3x.png');
            }
        }
        &.off {
           background-image: url('star24_off@2x.png');
            @media(-webkit-min-device-pixel-ratio: 3),(min-device-pixel-ratio: 3) {
             background-image: url('star24_off@3x.png');
            }
        }
      }
    }
    &.star-36 {
      .star-item {
        width: 15px;
        height: 15px;
        margin-right: 16px;
        background-size: 15px 15px;
        &:last-child {
          margin-right: 0;
        }
        &.on {
           background-image: url('star36_on@2x.png');
            @media(-webkit-min-device-pixel-ratio: 3),(min-device-pixel-ratio: 3) {
             background-image: url('star36_on@3x.png');
            }
        }
        &.half {
           background-image: url('star36_half@2x.png');
            @media(-webkit-min-device-pixel-ratio: 3),(min-device-pixel-ratio: 3) {
             background-image: url('star36_half@3x.png');
            }
        }
        &.off {
           background-image: url('star36_off@2x.png');
            @media(-webkit-min-device-pixel-ratio: 3),(min-device-pixel-ratio: 3) {
             background-image: url('star36_off@3x.png');
            }
        }
      }
    }
    &.star-48 {
      .star-item {
        width: 20px;
        height: 20px;
        margin-right: 22px;
        background-size: 20px 20px;
        &:last-child {
          margin-right: 0;
        }
        &.on {
           background-image: url('star48_on@2x.png');
            @media(-webkit-min-device-pixel-ratio: 3),(min-device-pixel-ratio: 3) {
             background-image: url('star48_on@3x.png');
            }
        }
        &.half {
           background-image: url('star48_half@2x.png');
            @media(-webkit-min-device-pixel-ratio: 3),(min-device-pixel-ratio: 3) {
             background-image: url('star48_half@3x.png');
            }
        }
        &.off {
           background-image: url('star48_off@2x.png');
            @media(-webkit-min-device-pixel-ratio: 3),(min-device-pixel-ratio: 3) {
             background-image: url('star48_off@3x.png');
            }
        }
      }
    }
  }
</style>